Shipped with a wall charger and USB cable, PaySaber Clip ($80) is USAePay's first portable point-of-sale system for all iOS users, bringing features from its prior iPhone- and iPod touch-compatible units to a design that works equally well with the iPad. Contrasting with the diminutive Square Reader and Intuit GoPayment systems, PaySaber Clip has a three-track bi-directional credit card reader and end-to-end data encryption system inside a much larger, clip-based housing. A USB port provides a pass-through route for an included USB cable and wall charger to refuel your iOS device during use. Several free applications are available to enable payment processing using the hardware, however, unlike Square's free hardware and wholly transaction-based percentage system, USAePay's pricing approach is different. You can pay $80 outright for the more premium card-swiping terminal, or get it for free with a 12-month commitment to recurring merchant fees of $10 or more, atop per-transaction costs of $0.20 per charge plus 0.69%-1.69% of the transaction amount.

Editors' Note: iLounge only reviews products in "final" form, but many companies now change their offerings - sometimes several times - after our reviews have been published.
This iLounge article provides more information on this practice, known as revving.